1. Field of the Invention
This invention relates to terbium-activated rare earth oxysulfide phosphors. More particularly it relates to terbium-activated rare-earth oxysulfide phosphors having closely-controlled decay characteristics.
2. Prior Art
The luminescent properties of rare earth oxysulfide phosphors are known. They are used in a variety of uses, for example, in color television, X-ray, and the like. In some instances these materials have decay characteristics which, if altered, could broaden their field of use. It is believed that materials of the rare-earth oxysulfide phosphor type which contain an additive that enables the decay characteristics to be changed in a controlled manner, would be an advancement in the art.